Compiled from open educational resources (OER) the courses are designed to act as a "textbook replacement or as a framework that teachers can supplement with their own curriculum materials," according to a company news release.

The courses are free and comprise more than 40 collections, designed for use in grades 6-12, in math, science, social studies, and English.

“The rapid proliferation of OER means educators have more options than ever to bring current, high-quality content to their students. But few educators have the time to navigate and sort through all the options, analyze the quality, and then cobble together the content to meet their grade-level standards,” said Michael Messner, Net Texts co-founder and CEO, in a prepared statement. “We created OER Textbook Replacement Courses to make it easy for teachers to replace textbooks with free, high-quality OER courses that they can use as-is or customize to meet their needs. With these courses, schools now have a practical alternative to purchasing expensive, soon-to-be outdated textbooks.”